Immersible electrodynamic loud



Oct. 13, 1953 J. D. SEABERT Re 23,724

IMMERSIBLE ELECTRODYNAMIC LOUD-SPEAKER Original Filed Jurie 29, 1944Suvelxtor JUHN D.' EEHEIERT Reissued Oct. 13, 1953 UNITED STATES PATENTIMMEasILI: ELEo'rRonYN-AMIG LOUD- AKER John D. Seabert, Haddon Heights,Ni J., assigner to Radio Corporation of America, a corpora- SPE tion ofDelaware Original No. 2,517,138, dated August 1, 1950, Se-

rial No. 542,745, .Tulle 29, 1944.

Application for reissue July: 28, 1951, Serial No. 239,125

12 ClaimsA Matter enclosed in heavy brackets l' appears in the originalpatent but forms no part` of this reissue specification; matter printedin italics indicates the additions made by reissue.

'I'his invention relates to signal translating apparatus, and moreparticularly to a loud-- speaker especially suitable for use as part ofan announce system or the like on submarines.

It has been found very expedient in naval craft to use telephone systemsor the like for communication between various parts of ships, forissuing orders, making announcements, etc. On submarines, it has beenfound desirable to employ announce systems utilizing loudspeakers whichare mounted on the bridge. Due to the fact that submarines must oftensubmergeV quickly, conventional loudspeakers are entirely unsuited forsuch operation.

The primary object of my present invention is to provide a novelloudspeaker which is especally useful on the bridges of submarines.

More particularly, it is an object of my present invention to provide animproved loudspeaker which can be` used in air and which can besubmerged in water Without requiring any alteration or protectivedevices before submersion.

Another object of my presentinvention is to provide an improvedloudspeakery as aforesaid which is capable of withstanding Waterpressure of the order of 200 pounds per square inch.

Still another object of my present invention is to provide an improvedloudspeaker as aforesaid which is instantly ready for operation whenbrought out of the waterl into the air.

It is also an object of my present invention to provide an improvedloudspeaker as aforesaid whichis fairly simple in construction, quiteeconomical in cost, and highly efficient in use..

In accordance with the present invention, I provide a water-tight casingwhich may comprise a pot and a removable cover therefor adapted to bearranged in water-tight relation With the pot. Within the pot is housedan electromechanical motor. This motor is preferably of theelectrodynamic type and includes a field structure arranged entirelyvwithin the pot of the casing. A voice coil assembly is vibrativelymounted on the inner surface of the cover and is connected by means of acoupling rod which passes through an opening in the cover to a soundradiating diaphragm which is vibratively carried by the cover on theoutside thereof. The diaphragm, which. is made of waterproof material,is exposed on both sides thereof to the ambient and may be protectedfrom injury by a suitable, perforated casing. A flexible seal surroundsthe. coupling rod in huid-tight relation therewith and covers theaforementioned opening so as to prevent water from entering into thecasing when the loudspeaker is submerged in water.

The diaphragm and the voice coil assembly operate in unison. in responseto actuating sig,- nal forces applied to the voice coil assembly by theelectromechanical motor, the coupling rod driving the diaphragm inresponse to movement of the voice coil assembly. Thus, the diaphragm canbe made to radiate sound when operating in the air. When the submarineis submerged, the water surrounds the diaphragm and, since it is exposedon both. sides to the water, the Water pressure is equalized againstboth surfaces thereof. At the same time, the water presses against theaforementioned seal around the drivingr rod and forces it against theopening in the cover through which the drive rody passes. In this way,water is prevented from entering the casing and injuring the partshoused therein. Cable conncctions` from the voice coil, field coil,transformers, and other parts of the loudspeaker mechanism within theycasing may be brought out from the. casing through suitable, watertightcouplings.

The novel features that I consider characteristie of my invention areset forth with. particularity in the appended claims. The inventionitself, however, both as to its organization and method of operation, asWell as additional objects and advantages thereof, will best beunderstood from the following description of one embodiment thereofwhen` read in connection with the accompanying drawing, in which Figure1- is a side view, partly in section, of one form. of loudspeakerconstructed according to my present invention, and

Figure 2 is a top, plan view thereof.

Referring more particularly to the drawing, wherein similar referencecharacters designate corresponding parts throughout, there is shown acasing comprising a box or pot I and a cover 3 hngedly connected to thepot I .and adapted to be clamped in water-tight relation therewiththrough' an. intervening gasket 5 by means of a plurality of bolts l.Within the pot I s housed a suitable electromechanical motor orconverter 9 whichA I have shown as being` of the` dynamic type, althoughit may be of any other suitable type. The motor 9 includes a fieldstructure II provided with an air gap I3.

Vibratively mounted on the inside of the cover 3 is a voice coilassembly comprising a small diaphragm or vibratory member I5 having avoice coil` I1V located in the air gap I3 in known man- A seconddiaphragm or vibratory member I9 is vibratively mounted between a pairof clamping members 2| and 22 and is connected to the diaphragm I by acoupling rod 23 which passes through an opening 25 in the coverll. Theassembly comprising the clamping members 2| and 22 and the diaphragm I9iscarried on the cover 3 and may be connected thereto by a plurality ofbolts or the like 2l. A flexible gasket 28 of rubber or any othersuitable material is clamped between the clamping member 22- and the topof the cover 3 and has an opening therein through which the coupling rod23 extends. The gasket 29 tightly embraces the coupling rod 23 and isarranged over the cover opening 25 to prevent the passage of water, air,or other iluid between the exterior and interior of the casing I, 3. Aplurality of openings 3! in the clamping member 22 and a perforatedprotective screen or the like 33 serve to expose both sides or surfacesof the sound radiating diaphragm I9 to the ambient, whether it be theair or the water. Connection of the loudspeaker to suitable externalapparatus, such as a microphone, an amplifier, batteries and the likemay be made through suitable Huid-tight couplings 35 in well knownmanner.

A loudspeaker such as described above may be mounted on the bridge of asubmarine or in any other suitable location as a part of an announcesystem or the like. During operation in the air, signal forces appliedto the motor 3 effect vibration of the diaphragm I5 which, in turn,drives the diaphragm i9 through the coupling rod 23 to radiate sound.The seal 29 is suiliciently iiexible to permit substantially unhamperedvibration of the vibratory system. When the submarine is submerged, thewater surrounds the diaphragm I9 with equal pressure on both sidesthereof and it also presses the seal 29 against the cover 3. Since thecasing i, 3 is fluid-tight, no water will enter therein. The diaphragmI9 is made of suitable, waterproof material, such as cloth impregnatedwith Bakelite or other suitable, resinous-materialJ and, since the waterpressure on both sides thereof is equal, it willnot be damaged. I havefound that water pressures of the order` of 20G pounds per square inchhave failed to damage the diaphragm I9. Thus, no protective devices needbe applied to this loudspeaker before the submarine is submerged. Whenthe submarine rises to the surface, the loudspeaker is immediately readyfor operation without requiring any adjustments or manipula tions torender it suitable for use.

Although I have shown and described but one form of my presentinvention, it will undoubtedly be apparent to those skilled in the artthat many other forms thereof, as well as variations in the particularone described, are possible within the spirit of my invention. Itherefore desire that my invention shall not be limited except insofaras is made necessary by the prior art and by the spirit of the appendedclaims.

I claim as my invention:

1. In signal translating apparatus, the combination of a fluid-tightcasing having a hinged cover provided with an opening, anelectromechanical converter including a rst vibratory member Within saidcasing, a second vibratory member outside of said casing, means couplingsaid rst and second vibratory members for movement in unison, saidcoupling means comprising an element passing through said opening, saidhinged cover supporting said iirst and second vibratory members andcontaining a ilexible seal over said opening and around said element influid-tight relation therewith for preventing the passage of uid betweenthe exterior and interior of said casing, the exibility of said sealpermitting substantially unhampered movement of said element and saidvibratory members, and limiting means carried by said hinged cover forlimiting inward movement of said exible seal when said apparatus issubjected to abnormal, external fluid pressure.

2. In signal translating apparatus, the combination of a fluid-tightcasing having a hinged cover provided with an opening, anelectromechanical converter including a rst vibratory member within saidcasing, a second vibratory member outside of said casing, said hingedcover including supporting means for each of said vibratory members,said second vibratory member-supporting means having apertures thereinfor exposing both sides of said last named member to the ambient, meanscoupling said iirst and second vibratory members for movement in unison,said coupling means comprising an element passing through said opening,a fiexible seal over said opening and around said element in fluid-tightrelation therewith for preventing the passage of iuid between theexterior and interior of said casing, the flexibility of said sealpermitting substantially unhampered movement of said element and saidmembers, and means for limiting inward movement of said iexible sealwhen said apparatus is subjected to abnormal, external fluid pressure.

3. In signal translating apparatus, the combination of a duid-tightcasing having a hinged cover provided with an opening, anelectromechanical converter including a rst vibratory member within saidcasing, a second vibratory member outside of said casingJ said hingedcover including supporting means for each of said vibratory members, aperforated auxiliary housing for said second vibratory member on saidcover for exposing both sides of said last named member to the ambient,means coupling said rst and second vibratory members for movement inunison, said coupling means comprising an element passing through saidopening, a ilexible seal over said opening and around said element influid-tight relation therewith for preventing the passage of fluidbetween the exterior and interior of said casing, the iiexibility ofsaid seal permitting substantially unhampered movement of said elementand said members, and means :for limiting inward movement of saidiiexible seal when said apparatus is subjected to abnormal, externaliiuid pressure.

4. In a loudspeaker, the combination of a duid-tight casing having ahinged cover provided with an opening therein, an electromechanicalmotor including a vibratory member supported within said casing by saidcover, a vibratory diaphragm supported outside of said casing by saidcover, means coupling said vibratory diaphragm to said vibratory memberfor movement in unison therewith in response to actuating forces appliedto said vibratory member by said motor, said coupling means comprisingan element passing through said opening, a flexible seal over saidopening and around said element in uidtight relation therewith forpreventing the pasysage of iluid between the exterior and interior ofsaid casing, the flexibility of said seal permitting substantiallyunhampered movement of said element, and limiting means carried lby saidcover for limiting inward movement of said ilexible seal when saidloudspeaker is subjected to abnormal, external fluid pressure.

5. In a loudspeaker, the combination of a fluidtight casing having ahinged cover provided with an opening, an electromechanical motorincluding a vibratory member supported by said cover ,and disposedwithin said casing, a vibratory diaphragm supported by said cover anddisposed on the outside of said casing, the support for said diaphragmhaving apertures therein for exposing both sides of said diaphragm tothe ambient, means coupling said diaphragm to said vibratory member formovement in unison therewith in response to actuating forces applied tosaid vibratory member by said motor, said coupling means comprising anelement passing through said opening, a flexible seal over said openingand around said coupling means in Huid-tight relation therewith forpreventing the passage oi' uid between the exterior and interior of saidcasing, the iiexiblity of said seal permitting substantially unhamperedmovement of said coupling means, and additional means carried by saidcover for limiting inward movement of said flexible seal when saidloudspeaker is subjected to abnormal, external uid pressure.

6. In a loudspeaker, the combination of a uidtight casing comprising apot and a hinged cover adapted to be brought into fluid-tight relationwith said pot, an electromechanical motor mounted within said pot, saidmotor including a first vibratory diaphragm, a second vibratorydiaphragm carried by said cover on the outside thereof, said hingedcover including a peripheral support for each of said diaphragms, saidrst diaphragm being concealed Within said casing, said second diaphragmsupport having apertures therein for exposing both sides of said lastnamed diaphragm to the ambient, and means coupling said diaphragms toeach other for movement in unison in response to actuating forcesapplied to said rst diaphragm 'by said motor.

7. In a loudspeaker, the combination of a fluid-tight casing comprisinga pot and a cover adapted to be brought into fluid-tight relation withsaid pot, an electromechanical motor of the dynamic type within saidcasing and including a iield structure housed within said pot, saidmotor also including a first diaphragm vibratively mounted on the insideof said cover, a second diaphragm vibratively mounted on the outside ofsaid cover, a peripheral support for each of said diaphragme, saidsecond diaphragm support having apertures therein for exposing both sideof said last named diaphragm to the ambient, and means coupling saiddiaphragms to each other for movement in unison in response to actuatingforces applied to said first diaphragm by said motor.

8. In a loudspeaker, the combination of a casing comprising a pot and acover hingedly connected to said pot and adapted to be brought intoclosed, uuid-tight relation with said pot, |an electromechanical motorwithin said pot, said motor including a rst vibratory diaphragmconcealed Within said casing when said cover is closed, a secondvibratory diaphragm carried by said cover outside of said pot, aperipheral support for each of said diaphragms, said second diaphragmperipheral support having apertures therein for exposing both sides ofsaid last named diaphragm to the ambient, and means coupling saiddiaphragms to each other for movement in unison in response to actuatingforces applied to said rst diaphragm by said motor.

9. A loudspeaker according to claim 8 characterized in that said motoris of the dynamic type and includes a eld structure within said pot,said eld structure having anair gap, and characterized further in thatsaid first diaphragm is also vibratively carried by said cover but onthe inside thereof, said first diaphragm including an operating coiladapted to be received in said air gap when said cover is closed.

10. In signal translating apparatus, the combination of .a fluid-tightcasing lhaving a cover provide-d with an opening, an electromechanicalconverter including a first vibratory member within said casing, asecon-d vibratory member outside of said casing, said cover includingsupporting means for each of said vibratory members, said secondvibratory member supporting means having apertures therein for exposingboth sides of said last-named member to the ambient, means coupling saidvibratory members for movementin unison, said coupling means comprisingan element passing through said opening, said cover containing aflexible seal over said Opening and around said element in fluid-tightrelation therewith for preventing the passage of fluid between theexterior and interior of said casing, and the flexibility of said sealpermitting substantially unhamperred movement vof said element and saidvibratory members.

11. In signal translating apparatus, the combination of a fluid-tightcasing having a cover provided with an opening, an electromechanicalconverter including a first vibratory member within said casing, asecond vibratory member outside of said casing, said cover includingsupporting means for each lof said vibratory members, a perforatedaumilirg housing for said second vibratory member on said cover for ea:-posing both sides `of said last named member to the ambient, meanscoupling said first and second vibratory members for movement in unison,said coupling means comprising an element passing through said opening,and a flexible seal over said opening and around said element influid-tight relation therewith for preventing the passage `of fluidbetween the exterior and interior of said casing.

12. In a signal translating apparatus, the combination of a fluid-tighteasing comprising a pot and a cover adapted to be brought intofluidtight relation with said pot, said pot and cover excluding theambient, an electromechanical motor mounted within said pot, said motorincluding a first vibratory member, a second vibratory member carried bysaid cover on the outside thereof, said cover including a support forsaid second vibratory member, said first vibratory member beingconcealed within said casing, and said second vibratory member supporthaving apertures therein for exposing both sides of said last namedvibratory member to the ambient, and means coupling saidvibratorymembers to each other for movement in unison.

JOHN D. SEABERT.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS Number Name Date 352,472 Lungen Nov. 9, 1886353,274 Tucker et al Nov. 23, 1886 1,523,964 Horig Jan. 20, 19252,236,973 King Apr. 1, 1941 2,276,022 Cox Mar. 10, 1942 2,346,429Harrison Apr. 1l, 1944 2,400,281 Anderson May 14, 1946

